We travel a lot. We used to have a hard-shell rooftop carrier, but it was a huge pain. in addition to being bulky, the straps were always making lots of noise while driving. After getting a station wagon with a roof rack and making a final attempt to makeshift something that wouldn't be noisy (which didn't work), we decided to go with a soft car top carrier.
The Thule Escape II fit our needs. We wanted a lot of cargo space, and something that could be easily stored. The first time we used it, we drove through a major Cleveland snowstorm/windstorm, and we had a couple of items that got slightly damp. This was a pretty exceptional storm - we actually spent some time at the side of the road because the driving conditions were so bad. Other than that, we have not had any issues when driving through snow and rain.
The straps make it easy to attach to the roof rack, and we can put it on in less than 5 minutes. It does what it's supposed to, and we're happy with our purchase!